Coking hydrocarbon oils



Sept. 1o, 1935. f J, SEGUY 2,014,212

COKING HYDROCARBON OILS Filed April Y30, 1932 LA frac iowa (orCombustion gases and Vaporous hydrocarbons,

resulting from coking of the oil, are removedv from the coking zonethrough line 2|, valve 22 and are introduced into fractionator or tarseparator 23 wherein the heaviest components of the vapors, comprisingtars and other materials of high coke-forming characteristics areseparated from the lighter vapors and gases. The heavy high coke-formingoils are withdrawn from fractionator 23 .through line 24 and valve 25 topump 26 by means of which they are returned through line 21 and valve 28to the manifolds 3, preferably at a point between two of the larger ofthe nozzles 5, through which the oil from zone 23 is introduced into thecoking zone, together with charging stock from line I, and theresubjected to further coking.

Vapors escaping condensation in column 23 are withdrawn through line 29and valve 3|) to further fractionation in fractionator 3| by means ofwhich additional liquid components of the vapors of lower boilingAcharacteristics than the heavy tars separated in fractionator 23 and ofhigher boiling characteristics. than the desirable light liquid productof the system are condensed as reflux condensate which collects in thelower portion of fractionator 3| and may be withdrawn through line 32and valve 33 to cooling and storage or to any desired further treatment,and may, when desired, be recycled to further conversion in the samecracking system from which the residual oil to be coked is obtained,when the oil to be coked is obtained from such a source.

Vapors and gases remaining uncondensed in fractionator 3| are withdrawnthrough line 34 and valve 35 to condensation and cooling in condenser 36wherefrom the condensed and uncondensed materials pass through line 31and valve 38 to be collected in receiver 39. i Uncondensed products,including combustiony gases, hydrocarbon gases and entrained liqueiiablehydrocarbons may be released from receiver 39 through line 40 and valve4| and are preferably subjected to absorption or scrubbing, by wellknown means not shown in the drawing, for the removal of the de- Sirablelight liquefiable hydrocarbons which may be blended back with thedistillate withdrawn from receiver 39 through -line 42 and valve 43,this blended product forming the desirable light liquid' product of thesystem which preferably comprises materials boiling Within the range ofmotor fuel and of high anti-knock value. A portion of the gas withdrawnfrom receiver 39 or preferably a portion of the lean gas from theprocess, i. e. gas from receiver 39 afterscrubbing or absorption, forthe removal of liqueiiable components, may be returned to combustionzone 6 to serve as a portion or all of the fuel required by the process.Line 44, controlled by valve 45, serves as a means of removing gas forthis purpose from receiver 39 and line 45', controlled by valve 46,serves as a means of returning the lean gas. Either of these gases thussupplied to pump or compressor 41 are returned through line 48 and valve49 to burner 9 and thence to combustion zone 6.

Pump 41 may serve as a vacuum pump for maintaining sub-atmosphericpressure in the coking zone and succeeding portions of the system or,when desired, a vacuum pump may be interposed, for example, in line 2|or in line.29 for the purpose of maintaining subatmospheric pressure inthe coking zone alone or in the coking zone and any desired portion ofthe succeeding equipment, although such means are not illustrated in thedrawing. v

As already mentioned, the combustion zone mayfbe operated atsubstantially atmospheric or 5 low superatmospheric pressure up to 60pounds, or thereabouts, per square inch. The coking zone may be operatedat substantially atmospheric orr subatmospheric pressure. Temperaturesemployed in the coking zone may range from 1200 to 10 1600 F., orthereabouts. The portions of the system succeeding the coking zone maybe operated at substantially equalized or increased pressure relative tothat employed in the coking zone.

As a specic example of the operation of the 15 process of the presentinvention, heavy residual oil resulting from cracking is introduced intothe coking zone through a plurality of streams of progressivelydecreasing size at a temperature of approximately 780 F. Hot combustiongases 20 generated under a superatmospheric pressure of about 10 poundsper square inch are passed through the cokingzone and directly contacted`continuously withdrawn from the coking zone and a portion of the leangas from the system is returned to the combustion zone as fuel. Thisoperation may yield, per barrel of charging stock, about pounds of cokeof low volatility, about 35 8 gallons of distillate boiling within therange of motor fuel and having an octane number of approximately 82. Theother products of thesystem comprise about 'l1/2 gallons of intermediateY liquid products suitable for use as cracking stock 40 and about 3500cubicfeet of gas, per barrel of charging stock. The gas is a mixture ofhydrocarbon gases and combustion gases and may have a calorific value ofabout 500 B. t. u.s

I claim as my invention: 45

1. In a process for the continuous coking of hydrocarbon oil wherein theoil Ais introduced into a coking zone and there directly contacted withhot combustion gases whereby said oil is reduced to coke, theimprovement which comprises in- 50 troducing the oil into the cokingzone in a plurality of streams of graduated and progressively smallercross-section, and passing the combustion gases through the coking zonein the direction of decreasing cross-section of said streams. 55

2. A process such as isy claimed in claim 1 wherein subatmosphericpressure is employed in the coking zone.

3. A process for the coking of hydrocarbon oils which comprisesintroducing the oil into a. cok- 00 ing zone in a plurality of streamsof graduated and progressively smaller cross-section, generatingcombustion gases in a combustion zone and passing the hot combustionproducts through the coking zone in the direction of decreasing cross-65 section of said streams, whereby the oil is reduced to coke, removingcoke from the coking zone, removing Vaporous and gaseous hydrocarbonstogether with combustion gases from the 70 coking zone, separating fromthe mixture of vapors and gases heavy tars and similar coke-formingmaterials, returning the latter to the coking zone, then cooling themixture of vapors and gases to condense Vaporous hydrocarbons con- 75tained therein and returning atleast a portion oi' comprises introducingthe oil to the coking zone the latter gaseous hydrocarbons to thecombusin a plurality of streams at longitudinally spaced tion zone toserve as fuel for the process. points between said ends of the cokingzone, said 4. In the cokingr of hydrocarbon o'il in a cokstreams beingof progressively smaller cross-sec- 5 ing zone wherein progressivelydecreasing temtion in the direction o! decreasing temperatures 5peratures prevail from one end of the coking zone through the cokingzone. to the other end thereof, the improvement which JEAN DELA'I'I'RESEGUY.

